The special committee investigating the manufactured traffic jam at the George Washington Bridge plans to issue a subpoena for Gov. Chris Christie’s re-election campaign organization, a source involved in the probe told NBC News on Thursday.

The chairman of the committee had planned to subpoena only Bridget Kelly, Christie’s since-fired deputy chief of staff, and Bill Stepien, who managed both of the governor’s campaigns, the source said.

Three organizations and 17 people are receiving subpoenas in the investigation into the bridge traffic scandal that rocked New Jersey and its governor, Chris Christie. NBC's Kelly O'Donnell reports.

But the subpoena list grew after the committee hired Reid Schar, a high-powered former federal prosecutor, the source said. The chairman, Assemblyman John Wisniewski, told reporters that roughly 20 subpoenas would be issued — 17 people and three organizations, all in New Jersey.

Subpoena targets include David Samson, the Port Authority’s chair, and Regina Egea, Christie’s next-in-line to be chief of staff.

Those subpoenaed will have about two weeks to respond, Wisniewski said, adding that he doesn't expect the committee to meet until mid-February.

The committee was formed by the state Assembly to look into why lanes from Fort Lee, N.J., onto the bridge were closed for four days in September, outraging drivers, slowing emergency vehicles and practically turning the city into a parking lot.

Emails and other documents that have surfaced since last week suggest that the lanes were closed as an act of political payback against the Democratic mayor of Fort Lee. The resulting scandal is the biggest of Christie’s career.

The governor last week fired Kelly, who sent the email last August — “Time for some traffic problems in Fort Lee” — that appeared to set the jam in motion. He also cut ties with Stepien.

“I was born here, I was raised here, I’m raising my family here, and this is where I intend to spend the rest of my life,” he said. “Whatever test they put in front of me, I will meet those tests because I’m doing it on your behalf.”

At an appearance with homeowners on the Jersey Shore, the governor took note of the large media contingent following him and said: “I hope all these people with cameras will frequent the local businesses.”

The committee held its first meeting Thursday and went into closed session to discuss subpoenas. Wisniewski said he wanted to make sure people receiving subpoenas find out through the appropriate channels, not from reporters.

Republicans on the committee were already raising questions about the conduct of the investigation. They objected to rules giving Wisniewski sole control over subpoenaed documents.

“We’re one hour into this process, and bipartisanship is already slipping away,” said Assemblyman Gregory McGuckin.

Wisniewski pledged to use the power fairly and invited Republicans to judge him by his conduct. He said that at this point in the investigation, the committee will not be subpoenaing documents from the governor.

Besides the special Assembly committee, inquiries or full-scale investigations have been promised by the state Senate, the bridge-controlling Port Authority, the U.S. Senate transportation committee and the Justice Department.

NBC's Michael Isikoff reports on the New Jersey legislature's investigation into the George Washington Bridge closures and why Democrats in the state believe this scandal is so serious.

Sen. Jay Rockefeller of West Virginia on Thursday released a 17-page letter from the Port Authority answering his questions about the matter. He said the Port Authority submission included “zero evidence” of a traffic study — the original explanation for the lane closures.

The Port Authority submission lays out concerns raised within the Port Authority before the lanes were closed, including that it would create serious congestion and raise the risk of collisions. It says that David Wildstein, a Christie appointee at the Port Authority, ordered and oversaw the lane closures.

Wildstein, who has since resigned, was the recipient of Kelly’s “Time for some traffic problems” email on Aug. 13. The lane closures began Sept. 9.

Christie’s office announced Thursday that it had hired a prominent law firm to help with its internal investigation, and to cooperate with the inquiry opened by the Justice Department.

Christie’s legal team will be headed by Randy Mastro, a former federal prosecutor in New York who specialized in organized crime cases, and a former chief of staff to then-New York Mayor Rudy Giuliani.

Schar, counsel for the special Assembly committee, helped convict former Illinois Gov. Rod Blagojevich in 2011 of trying to sell President Barack Obama’s vacated Senate seat.